Microcontrollers are used in myriad devices and systems to implement one or more control and/or monitoring schemes. For example, many aircraft engines are controlled via an engine controller, such as a digital electronic engine controller (DEEC) or a full authority digital engine controller (FADEC), that may be implemented using a plurality of microcontrollers. The microcontrollers may receive various command signals, and a plurality of signals representative of various physical and/or operational parameters and, implementing one or more control laws via an on-board central processing unit (CPU), control the overall operation of the aircraft engine to achieve the desired performance.
In many instances the physical and/or operational parameter signals supplied to the microcontrollers are analog signals, which may need to be converted to digital signals for further processing. Thus, many microcontrollers, such as those that are used in aircraft engine controllers, include one or more analog-to-digital converters (ADCs). The ADCs included in some microcontrollers are so-called “queued” ADCs (QADCs). A QADC includes a queue that is used to store various commands and to run the stored commands independent of the CPU.
The microcontrollers that are presently used in engine controllers and various other aircraft-related systems and devices, whether implemented with one or more QADCs or various other types of ADCs, are generally robust and generally operate reliably and safely. However, these devices do suffer certain drawbacks. In particular, the ADCs typically exhibit two performance limitations. These limitations include the number of available external address bits, and the maximum settling time to which the ADC can be set.
Hence, there is a need for a circuit and method that can extend the number of available external address bits and/or the maximum settling time of an ADC, preferably without relying on microcontroller CPU intervention. The present invention addresses at least this need.